Add changesources.g script for updating manual examples

Author: fingolfin

changesources.g

@@ -0,0 +1,7 @@
+# Update the examples in the manual to match the output of the GAP
+# version used to process this file
+example_tree := ExtractExamples( Directory("./doc/"), "forms.xml",[], 500);;
+RunExamples(example_tree, rec(
+    changeSources:=true,
+    width := 80,
+));